ESTIMATION OF THE UNCERTAINTIES ASSOCIATED WITH XPS PEAK INTENSITY DETERMINATION

Formulae are presented for estimation of the statistical uncertainties (standard deviations) associated with the peak heights and integrated intensities (areas) required for elemental quantification in XPS in situations where peak overlap is not significant. The situation arising when curve-resolution procedures are used to separate discrete XPS signals for quantification is discussed, and a simple, rapid, but approximate procedure to estimate standard deviations for both the parameters characterizing the fit and the overall component intensities is developed. Both minimum-chi-2 and unweighted least-squares procedures are considered. Some difficulties in relation to background subtraction and the inevitable presence of systematic errors in most XPS curve-fitting procedures are identified and discussed.